Prosthetic heart valve sizer assembly with flexible sizer body

ABSTRACT

A flexible sizer body for evaluating a valve annulus to determine a size of a prosthetic heart valve to be sewn to the valve annulus during heart valve replacement surgery. The prosthetic heart valve includes an annular extension having a first flexibility and a sewing ring having a second flexibility. The flexible sizer body includes an outer ring and an annular wall coupled to and extending from the outer ring. The annular wall has a flexibility substantially similar to the first flexibility of the annular extension of the prosthetic heart valve.

BACKGROUND OF THE INVENTION

The present invention relates to a sizer for implantable prostheticheart valves. More particularly, the present invention relates to asizer for more precisely determining the proper size of a prostheticheart valve to be implanted during heart valve replacement surgery.

Various types and configurations of prosthetic heart valves, used toreplace diseased natural human heart valves, are known in the art. Theactual shape and configuration of any particular prosthetic heart valveis, of course, dependent to some extent upon the valve being replaced(i.e., mitral valve, tricuspid valve, aortic valve, and pulmonaryvalve). In general terms, however, the prosthetic heart valve designattempts to replicate the function of the valve being replaced and thuswill include valve leaflet like structures. With this in mind,prosthetic heart valves including valve leaflets are generallycategorized as either forming relatively flexible leaflets or relativelyrigid leaflets.

The category including prosthetic heart valves which form relativelyflexible leaflets includes bioprosthetic heart valves having leafletsmade of a biological material as well as prosthetic heart valves havingleaflets made of synthetic (e.g., polymeric) material. Flexible leafletprosthetic heart valves are generally categorized as having a frame orstent or as having no stent. The stent in a stented prosthetic heartvalve normally includes a substantially circular base or stent ringaround which an annular suture material is disposed for suturing theprosthesis to heart tissue. The stent ring including the annular suturematerial is typically referred to as a sewing ring. Further, the stentforms at least two, typically three, support structures extending from astent ring. The support structures are commonly referred to as stentposts or commissure posts and include an internal, rigid yet flexiblestructure extending from the stent ring, covered by a cloth-likematerial similar to that of the annular suture material. The stent orcommissure posts define the junction between adjacent tissue orsynthetic leaflets otherwise secured there too.

Examples of prosthetic heart valves are described in U.S. Pat. No.4,106,129 to Carpentier et al. and U.S. Pat. No. 5,037,434 to Lane, theteachings of which are incorporated herein by reference. Thesedisclosures detail a conventional configuration of three leafletswherein one leaflet is disposed between each pair of stent or commissureposts. The Hancock® Modified Orifice Aortic Bioprosthesis and theHancock® II Bioprosthesis, both manufactured by Medtronic, Inc.,Minneapolis, Minn., are commercially available examples of bioprostheticvalves. Both the Hancock® Modified Orifice Bioprosthesis and theHancock® II are available in various sizes such that they may beimplanted in patients having corresponding varying sizes of heart valveannuli.

Prosthetic heart valves categorized as forming relatively rigidlyleaflets include mechanical prosthetic heart valves. A typicalmechanical heart valve includes an annular valve housing or body toprovide a passageway for blood flow. Relatively rigid leaflets arerotatably mounted to the annular housing and rotate to open or close theblood flow passageway. The Medtronic Hall® mechanical heart valve,manufactured by Medtronic, Inc., Minneapolis, Minn., is a commerciallyavailable example of a mechanical heart valve. Similar to bioprostheticvalves, mechanical heart valves are available in various sizes such thatthey may be implanted in patients having corresponding varying sizes ofheart valve annuli.

During valve replacement surgery, the heart valve prosthesis, whether itbe a bioprosthesis or a mechanical heart valve, is implanted within thepatient's heart either in a supra-annular or intra-annular implanttechnique. The supra-annular implant technique sutures the prostheticheart valve above the annulus corresponding to the heart valve to bereplaced. The intra-annular implant technique sutures the prostheticheart valve within the annulus corresponding to the heart valve to bereplaced.

Ideally, the heart valve annulus is formed of relatively healthy tissuereceptive to some shaping by the surgeon in preparation of receiving theheart valve prosthesis. However, due in part to the space and timeconstraints during valve replacement surgery, the shape of the resultingannulus is often less than perfect for the attachment of a heart valveprosthesis. At times, the annulus and/or the patient's natural leafletsare calcified, requiring complete annular debridement or removal of thehardened tissue. The annular debridement results in a less definedannulus ledge and larger overall orifice into which, or above which, theprosthetic heart valve is to be attached. As such, the size and contourof each annulus varies widely from patient to patient.

Due to the uneven nature of the annuli, it is crucial that a surgeonselect a properly sized prosthetic heart valve to match a particularpatient's annulus. Typical annulus sizers are simple cylinders made outof rigid plastics, wherein the cylinder diameter corresponds to a sizeof a particular prosthetic heart valve. During surgery, a surgeontypically has a number of sizers at his or her disposal, each sizerhaving a different size or diameter (i.e., each sizer relating to adifferent size of prosthetic heart valve). A surgeon inserts the sizeror a series of different sizers into the valve opening to measure thesize of the valve opening. Upon determining the size of the valveopening, the surgeon selects a heart valve prosthesis for implantationhaving a size believed to correspond to the size of the valve opening.

Although typical annulus sizers are rigid, the sewing or attachment ringincluded on prosthetic heart valves are flexible. When inserted withinor above the valve annulus, the sewing ring compresses and conforms moreclosely to the heart valve annulus. Where the selected heart valveprosthesis has a diameter substantially identical to the rigid sizerotherwise found to best “match” the annulus, this compression orconformity may result in the selected prosthetic heart valve being toosmall for the valve opening or annulus. Other times, a heart valveprosthetic sized to fit the valve opening may be too large forattachment to an unusually small annulus ledge. Accordingly, typicalprosthetic heart valve sizers often erroneously suggest the size ofprosthetic heart valve to be implanted. In such a case, the selectedprosthetic heart valve is discarded and a new prosthetic heart valve ischosen. Not only is this a waste of the relatively expensive valveprosthesis, but it is also a waste of time, which is often critical tothe patient's well being in valve replacement surgery. Therefore, inlight of the above, a need exists for a prosthetic heart valve sizerthat more accurately represents the actual size and flexibility of theprosthetic heart valve to be implanted.

SUMMARY OF THE INVENTION

An aspect of the present invention relates to a flexible sizer body forevaluating a valve annulus to determine a size of a prosthetic heartvalve to be sewn to the valve annulus during heart valve replacementsurgery. The prosthetic heart valve includes an annular extension havinga first flexibility and a sewing ring having a second flexibility. Theflexible sizer body includes an outer ring and an annular wall coupledto and extending from the outer ring. The annular wall has a flexibilitysubstantially similar to the first flexibility of the annular extensionof the prosthetic heart valve.

Another aspect of the present invention relates to a sizer forevaluating a valve annulus to determine a size of a prosthetic heartvalve to be sewn to the valve annulus during heart valve replacementsurgery. The prosthetic heart valve including an annular extensionhaving a first flexibility and a sewing ring having a secondflexibility. The sizer includes a handle defining a first end and asecond end, and a flexible sizer body coupled with the first end of thehandle. The flexible sizer body includes an outer ring and an annularwall coupled to and extending from the outer ring. The annular wall hasa flexibility that approximates the flexibility of the annular extensionof the prosthetic heart valve.

Another aspect of the present invention relates to a method forevaluating a valve annulus to determine a proper size of a prostheticheart valve to be sewn to the valve annulus during heart valvereplacement surgery. The prosthetic heart valve includes an annularextension having a first flexibility and a sewing ring having a secondflexibility. The method includes providing a flexible sizer body,inserting the flexible sizer body into an opening of the heart valveannulus to determine whether the flexible sizer body properly fits andconforms with the heart valve annulus, and selecting the prostheticheart valve to be sewn in the heart valve annulus based upon thedetermination of whether the flexible sizer body properly fit andconformed with the heart valve annulus. The flexible sizer body includesan outer ring and an annular wall. The annular wall is coupled to andextends from the outer ring. The annular wall has a flexibility thatapproximates the flexibility of the annular extension of the prostheticheart valve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective and exploded view of one embodiment of aprosthetic heart valve sizer assembly with a flexible sizer body inaccordance with the present invention;

FIG. 2A is a perspective view of one embodiment of a bioprosthetic heartvalve corresponding to the flexible sizer body illustrated in FIG. 1;

FIG. 2B is a perspective view of one embodiment of the flexible sizerbody illustrated in FIG. 1;

FIG. 2C is a perspective view of another embodiment of the flexiblesizer body illustrated in FIG. 1;

FIG. 2D is a perspective view of another embodiment of the flexiblesizer body illustrated in FIG. 1;

FIG. 3 is a top view of one embodiment of the flexible sizer bodyillustrated in FIGS. 2B, 2C, and 2D;

FIG. 4 is an illustration of the prosthetic heart valve sizer assemblybeing used during valve replacement surgery;

FIG. 5 is a perspective view of another embodiment prosthetic heartvalve sizer assembly including a flexible sizer body in accordance withthe present invention;

FIG. 6A is a perspective view of one embodiment of a mechanicalprosthetic heart valve corresponding to the flexible sizer bodyillustrated in FIG. 5;

FIG. 6B is a perspective view of one embodiment of the flexible sizerbody illustrated in FIG. 5;

FIG. 7 is a perspective view of an alternative embodiment prostheticheart valve sizer assembly including a flexible sizer body in accordancewith the present invention; and

FIG. 8 is a perspective view of an alternative embodiment prostheticheart valve sizer assembly including a flexible sizer body in accordancewith the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One preferred embodiment of a prosthetic heart valve sizer assembly 10is illustrated in FIG. 1. The sizer assembly 10 generally includes ahandle 12 and a flexible sizer body 14 coupled with the handle 12. Thehandle 12 includes a shaft or a rod 16 defining a distal end 18 oppositea proximal end 20 (generally indicated in FIG. 1). The handle 12 alsodefines a connector 22 on the distal end 18 to interface with andfacilitate coupling of the sizer body 14 with the handle 12. Inparticular, the connector 22 is formed to facilitate a snap connection,a threaded connection, or any other spatially feasible andbiocompatible, selective or permanent attachment to the sizer body 14.

The shaft 16 is formed of a bendable, biocompatible metal including butnot limited to stainless steel or nitinol. Further, the handle 12preferably includes a grip portion 24 near the proximal end 20 thereofto aid a surgeon (not shown) in grasping and manipulating the handle 12.The grip portion 24 has a larger dimension or diameter than the shaft 16to facilitate ergonomic handling of the handle 12 by the surgeon. Thegrip portion 24 is preferably formed of a polymeric material tofacilitate gripping of the handle 12. Alternatively, other constructionsare equally acceptable, and the grip portion 24 can be eliminatedentirely.

The sizer body 14, which is selectively coupled to the connector 22, isrepresentative of a prosthetic heart valve, such as a bioprostheticheart valve 30 illustrated in FIG. 2A. In general terms, thebioprosthetic heart valve 30 includes a stent 32, a sewing ring 34 andleaflets 36. As is known in the art, the stent 32 provides a supportframework for the bioprosthetic heart valve 30. The stent 32 includes aninner frame member or stent ring 38, which typically defines a circularor parabolic ring, and stent posts 40.

Each of the stent posts 40 extends from the stent ring 38 and terminatesin a rounded tip or free end 42 opposite the stent ring 38. As is knownin the art, the internal structure of each of the stent posts 40 isformed as a stiff but resiliently bendable material. This constructionallows the stent posts 40 to be inwardly defected from the orientationillustrated in FIG. 2A by an external force, such as an external forcefrom an insertion handle to position the bioprosthetic heart valve 30,during use. Once this external force is removed, however, the stentposts 40 return to the original position illustrated in FIG. 2A.Finally, a cloth cover 44 is preferably formed over the stent ring 38and the stent posts 40. The cover 44 is formed of a biocompatible,fabric material. In general, the stent 32 and the cover 44 form anannular extension 47.

The sewing ring 34 is coupled to and extends around the stent ring 38opposite the stent posts 40. The sewing ring 34 serves as a flexibleflange for subsequent suturing of the bioprosthetic heart valve 30 to aheart valve annulus. The sewing ring 34 preferably includes a clothcover 46, similar to the cloth cover 44, to facilitate suturing of thesewing ring 34 to the stent 32 and the heart valve annulus.

Each of the leaflets 36 is sutured to the cloth cover 44. In particular,the leaflets 36 are sutured to the cloth cover 44 that covers the stentposts 40 such that each leaflet 36 extends between two of the stentposts 40. Each of the leaflets 36 is also sutured to the cloth cover 44covering the stent ring 38 between the two stent posts 40. The leaflets36 are made of biological or synthetic (e.g., polymeric) material andare configured to open and close to regulate blood flow when implanted.

Notably in view of the above description, the annular extension 47 has afirst flexibility and the sewing ring 34 has a second flexibility. Thefirst flexibility normally differs from the second flexibility. As such,the entire bioprosthetic heart valve 30 accordingly defines a variableflexibility. Further, it will be understood that the above describedbioprosthetic heart valve 30 is but one acceptable configuration, forexample, more or less than three of the stent posts 40 can be provided,the stent posts 40 may incorporate a different covering 44, and/or thecovering 44 may be eliminated.

The bioprosthetic heart valve 30 is available in a plurality of sizescorresponding to the plurality of sizes of annuli found in heart valvereplacement patients. In particular, the bioprosthetic heart valve 30has a sewing ring maximum diameter D_(A1) ranging from approximately 18mm to 30 mm. The bioprosthetic heart valve 30 also has a maximum stentdiameter D_(A2), which is less than the sewing ring maximum diameterD_(A1) and which ranges in sizes accordingly. An overall or maximumheight H_(A) also varies with differently sized bioprosthetic heartvalves 30.

With the above background in mind, one embodiment of the sizer body 14of the sizer assembly 10 (FIG. 2) corresponding to the exemplarybioprosthetic heart valve 30 of FIG. 2A is illustrated in FIG. 2B. Thesizer body 14 includes an outer ring 48 and an annular wall 50. Theouter ring 48 is sized and shaped in a similar manner as the sewing ring34 of the bioprosthetic heart valve 30. Accordingly, the outer ring 48has a circular or parabolic shape and contour substantially similar toor matching the shape and contour of the sewing ring 34, such that eachexposed dimension of the outer ring 48 is within 1 mm of thecorresponding exposed dimension of the sewing ring 34. The outer ring 48defines a maximum diameter D_(B1) substantially equal to the maximumsewing ring diameter D_(A1) of the bioprosthetic heart valve 30.Otherwise stated, the maximum diameter D_(B1) is within 1 mm of themaximum sewing ring diameter D_(A1). Furthermore, the outer ring 48 isformed with a flexibility representative of or approximating theflexibility of the sewing ring 34. Notably, a representative flexibilityis a flexibility in which the outer ring 48 deforms or conforms to anarea in a substantially similar manner under substantially similarexternal forces as the sewing ring 34 being represented. In other words,the outer ring 48 has a substantially similar flexibility as the sewingring 34. Preferably, the outer ring 48 has a flexibility within 5% to10% of the flexibility of the sewing ring 34. In one embodiment, theouter ring 48 has a flexibility in the range of 90 to 110% of the sewingring 34. The representative flexibility of the outer ring 48 is achievedby varying material thickness of the outer ring 48, by varying adurometer of the material from the outer ring 48, or by forming theouter ring 48 to include a stiffening element within an over-moldedelastomeric material as described below.

The annular wall 50 extends from the outer ring 48, in a similar manner,the stent posts 40 extend from the stent ring 38, terminating in roundedextremities or tips 52. The annular wall 50 is sized and shaped in asimilar manner as the stent 32 of the bioprosthetic heart valve 30.Therefore, with the embodiment of FIG. 2B, the sizer body 14representing the heart valve 30, which has three of the stent posts 40,will similarly form three of the rounded extremities 52. Alternatively,the annular wall 50 can form only two rounded extremities 52 to mimic atwo stent post-type bioprosthetic heart valve (not shown). Each of theextremities are sized and spaced from one another similar to how thestent posts 40 and free ends 42 (FIG. 2A) are sized and spaced from oneanother. Accordingly, the annular wall 50 extends from the outer ring 48to produce an overall height H_(B) of the sizer body 14 substantiallyequal to the overall height H_(A) of the bioprosthetic heart valve 30.

Further, the annular wall 50 defines a maximum wall diameter D_(B2)substantially equal to the maximum stent diameter D_(A2). Otherwisestated, the height H_(B) is within 1 mm of the height H_(A), and themaximum wall diameter D_(B2) is within 1 mm of the maximum stentdiameter D_(A2).

The annular wall 50 has a flexibility representative of or approximatingthe actual flexibility of the annular extension 47, i.e., the annularwall 50 has a flexibility similar to the flexibility of the annularextension 37. As such, the annular wall 50 is formed to be stiff butresiliently bendable so as to allow inward deflection of the roundedextremities 52 from the orientation shown in FIG. 2B upon application ofan external force, such as the external force of a prosthetic valveholder. Once this external force is removed, however, the roundedextremities 52 return to the position illustrated in FIG. 2B. In analternative embodiment, the sizer assembly 10 (FIG. 1) further includesa mechanism (not shown) for deflecting the rounded extremities 52similar to typical prosthetic valve holders, such as the “Holder forHeart Valve” described in U.S. Pat. No. 5,476,510 to Eberhardt et al.,the “Heart Valve System” described in U.S. Pat. Publication No.US20030125805A1 of Johnson et al., or the “Prosthetic Heart ValveSystem” described in U.S. Patent Application Ser. No. 60/345,297 filedJan. 2, 2003, all of which are incorporated herein by reference.

In one embodiment, the sizer body 14 is formed of at least oneelastomeric material including, but not limited to, santoprene, silicon,and polyurethane. The annular wall 50 achieves a representativeflexibility in a similar manner as described with respect to the outerring 48. The representative flexibility of annular wall 50 is achievedby varying the material thickness, by increasing the durometer of thematerial, and/or by placing a stiffening element within an over-moldedelastomeric material. Preferably, the annular wall 50 has a flexibilitywithin 5% to 10% of the flexibility of the annular extension 47. In oneembodiment, the annular wall 50 has a flexibility in the range of 90 to110% of the annular extension 147.

Furthermore, since the outer ring 48 and the annular wall 50 each have asize and shape approximating the size and the shape of the sewing ring34 and the stent 32, respectively, the overall size and shape of thesizer body 14 approximates the size and shape of the bioprosthetic heartvalve 30. Similarly, since the annular wall 50 and the outer ring 48each have different flexibilities representative of the firstflexibility of the stent 34 and the second flexibility of the sewingring 34, respectively, the overall sizer body 14 defines a variableflexibility. With this in mind, the variable flexibility of the sizerbody 14 is representative of or substantially equal to the variableflexibility of the bioprosthetic heart valve 30.

Notably, although the sizer body 14 is representative of thebioprosthetic heart valve 30, it is not necessary for the sizer body 14to include representations of the leaflets 36 as illustrated in FIG. 2B.However, in embodiments not illustrated, the sizer body 14 includesrepresentations of the leaflets 36. The sizer body 14 is preferablysterilizable for reuse. In particular, the sizer body 14 is preferablyformed such that the outer surfaces of the sizer body 14 aresubstantially continuous to promote the proper sterilization of thesizer body 14 between uses. In light of sterilization concerns, thesizer body 14 is formed without the cloth covers 44 and 46 (FIG. 2A)described above with respect to bioprosthetic heart valve 30.

An alternate embodiment of the sizer body 14′ of the sizer assembly 10(FIG. 1) corresponding to the exemplary bioprosthetic heart valve 30 ofFIG. 2A is illustrated in FIG. 2C. The sizer body 14′ includes an outerring 48′ and an annular wall 50′. The outer ring 48′ is sized and shapedin a similar manner as the sewing ring 34 of the bioprosthetic heartvalve 30. As such, the outer ring 48′ has a circular or parabolic shapecorresponding to the shape of the sewing ring 34. The outer ring 48′defines a maximum diameter D_(C1) substantially equal to, i.e. within 1mm of, the maximum sewing ring diameter D_(A1) of the bioprostheticheart valve 30. Furthermore, the outer ring 48′ is formed with aflexibility representative of or approximating the flexibility of thesewing ring 34. In other words, the outer ring 48′ has a substantiallysimilar flexibility as the sewing ring 34. The representativeflexibility of the outer ring 48′ is achieved by forming the outer ring48′ to include a stiffening element 54 within an over-molded elastomericmaterial 56. The stiffening element 54 is preferably formed of a thinwire or contoured thermoplastic material, such as polypropylene, celcon,or acetyl homopolar. In one embodiment, the elastomeric material 56 isone of the group of, but not limited to, santoprene, silicon, andpolyurethane.

The annular wall 50′ extends from the outer ring 40′, in a similarmanner as the stent 32 and the stent posts 40 extend from the stent ring38, terminating in rounded extremities or tips 52′. The annular wall 50′is sized and shaped in a similar manner as the stent 32 of thebioprosthetic heart valve 30. Therefore, with the embodiment of FIG. 2C,the sizer body 14 representing the heart valve 30, which has three ofthe stent posts 40, will similarly form three of the rounded extremities52′. Alternatively, the annular wall 50′ can form only two roundedextremities 52′ to mimic a two stent post-type bioprosthetic heart valve(not shown).

Accordingly, the annular wall 50′ extends from the outer ring 48′ toproduce an overall height H_(C) of the sizer body 14′ substantiallyequal to the overall height H_(A) of the bioprosthetic heart valve 30.In particular, the overall height H_(C) is within 1 mm of the overallheight H_(A). Further, the annular wall 50′ defines a maximum walldiameter D_(C2) substantially equal to the maximum stent diameterD_(A2). Otherwise stated, the maximum wall diameter D_(C2) is within 1mm of the maximum stent diameter D_(A2). The annular wall 50′ has aflexibility similar to the flexibility of the annular extension 37. Therepresentative flexibility of the annular wall 50′ is achieved byforming the annular wall 50′ to include a stiffening element 58 withinan over-molded elastomeric material 59. In one embodiment, thestiffening element 58 is preferably formed of a thin wire or contouredthermoplastic material, such as polypropylene, celcon, or acetylhomopolar. The stiffening element 58 is formed of the same materialhaving similar or different thicknesses or of a different materialhaving similar or different thickness as the material of the stiffeningelement 54. In one embodiment, the elastomeric material 59 is one of thegroup of, but not limited to, santoprene, silicon, and polyurethane. Theelastomeric material 59 can be formed at the same or at a differentthickness as the elastomeric material 56. In one embodiment, the sizerbody 14 (FIG. 2B) incorporates either the outer ring 48′ or the annularwall 50′.

Another alternate embodiment of the sizer body 14″ of the sizer assembly10 (FIG. 1) corresponding to the exemplary bioprosthetic heart valve 30of FIG. 2A is illustrated in FIG. 2D. The sizer body 14″ is similar tothe sizer body 14 (FIG. 2B) in all respects other than thosespecifically described herein. The sizer body 14″ includes an annularwall 50″ having rounded extremities 52″ similar to the annular wall 50(FIG. 2B) having rounded extremities 52 (FIG. 2B). However, the roundedextremities 52″ are permanently deflected inwardly an amountsubstantially similar to the amount in which the free ends 42 of thestent posts 40 deflect inwardly upon application of an external force ofan insertion handle, which will be used in the subsequent implantprocedure to position the bioprosthetic heart valve 30 within thepatient (not shown). The permanent deflection of the rounded extremities52″ can be achieved through a variety of methods that will be apparentto one of skill in the art. In one embodiment, the rounded extremities52″ are constructed so as to assume the permanently deflectedorientation of FIG. 2D such as by an internal frame component (e.g., thestiffening element 58 of FIG. 2C). In another embodiment, the annularwall 50″ is formed to be inherently flexible (e.g., akin to the annularwall 50 of FIG. 2B), and thus selectively deflectable from anon-deflected orientation (e.g., akin to the orientation of FIG. 2B) tothe deflected orientation of FIG. 2D by an external deflection device(not shown) otherwise coupled to the extremities 52″.

With reference to FIG. 3, the sizer body 14 (or the sizer body 14′ or14″) preferably further includes a handle reception area 60 to receivethe connector 22 of the handle 12 (FIG. 1). The handle reception area 60is sized and shaped to receive the connector 22 via a snap connection, athreaded connection, or any other biocompatible, selective or permanentcoupling method. Preferably, the handle reception area 60 issubstantially centered with respect to the outer ring 48 and the annularwall 50 to increase the ease of maneuverability of the sizer body 14 bythe surgeon. In one embodiment, the handle reception area 60 is centeredwith respect to the annular wall 50 and the outer ring 48 by a pluralityof spokes 62. Each of the plurality of spokes 62 is attached to andextends between the annular wall 50 and the handle reception area 60.The plurality of spokes 62 are circumferentially spaced around thehandle reception area 60. In a preferred embodiment, the plurality ofspokes 62 is limited in number to limit the obstruction of the surgeon'sview through the sizer body 14 caused by each of the plurality of spokes62. However, in other embodiments, the handle reception area 60 isattached to the annular wall 50 or the outer ring 48 via a solid,circumferential body.

With additional reference to FIG. 1, assembly of the sizer assembly 10includes mating the connector 22 of the handle 12 with the handlereception area 60 of the sizer body 14. Although illustrated as a snapconnection, in other embodiments the handle 12 is coupled with sizerbody 14 in one of a plurality of fashions including a threadedattachment or any other spatially feasible, biocompatible attachment. Inone embodiment, the handle 12 is selectively coupled with sizer body 14such that the handle 12 can be selectively removed from the sizer body14 and selectively coupled with other representative bodies (notillustrated). In an alternative embodiment, the handle 12 is permanentlycoupled with the sizer body 14.

During heart valve replacement surgery, the surgeon will have aplurality of sizer assemblies 10 or at least a plurality of bodies 14 athis or her disposal. Each of the sizer assemblies 10, or moreparticularly each sizer body 14, corresponds with a different size orversion of bioprosthetic heart valve 30 (an exemplary one of which isillustrated in FIG. 2A), i.e., is representative off or approximates thesize, shape, and variable flexibility of an available bioprostheticheart valve 30. The surgeon selects one of the plurality of sizerassemblies 10 or bodies 14 by grasping the grip portion 24 of the handle12 and inserting the distal end 18 of the sizer assembly 10 into anaortic root 64 of a patient's heart valve annulus 66 as illustrated inFIG. 4.

The surgeon maneuvers the sizer assembly 10 to position the sizer body14 above or within (dependent upon the implant technique being utilized)the heart valve annulus 66 to evaluate the fit of the selected sizerbody 14. Since the sizer body 14 has a size, shape, and variableflexibility representative of the corresponding bioprosthetic heartvalve 30, the sizer body 14 fits within and conforms to the structureswithin the aortic root 64 in a manner substantially similar to orsubstantially predictive of how the corresponding bioprosthetic heartvalve 30 would fit within and conform to the structures within theaortic root 64. With this in mind, the surgeon compares the conformityof the outer ring 48 to the heart valve annulus 66 and evaluates thefeasibility of subsequent suturing of the corresponding bioprostheticheart valve 30 (illustrated in FIG. 2A) to the heart valve annulus 66.Furthermore, the surgeon observes and evaluates the positioning of theannular wall 50 within the aortic root 64 to ensure there is adequatespace for the sizer body 14 and that the positioning of the annular wall50 will not cause unintentional blockage. Preferably, the surgeon alsoevaluates the deflection of the annular wall 50 to determine if there issufficient space between the annular wall 50 and the annulus 66 foraccessing the outer ring 48 for suturing.

If the surgeon determines that the selected sizer assembly 10, or moreparticularly the selected sizer body 14, is a satisfactory andappropriate fit to the particular patient's heart valve annulus 66, heor she removes the sizer assembly 10 and selects the size and type ofbioprosthetic heart valve 30 that corresponds with the sizer body 14 forsubsequent implantation. However, if the surgeon determines that thesizer body 14 size or type is inappropriate for implantation to apatient's annulus 66, the sizer assembly 10 is removed and a differentsized sizer body 14 or sizer assembly 10 is selected.

The newly selected sizer assembly 10 is inserted into the aortic root 64of the patient and evaluated in a similar manner as described above withrespect to the initially selected sizer assembly 10. This process isrepeated until the performing surgeon determines the sizer body 14 of aselected sizer assembly 10 to be representative of the appropriatebioprosthetic heart valve 30. At such a time, the sizer assembly 10 isremoved, and a bioprosthetic heart valve 30, which corresponds to thesizer body 14 determined to be appropriate by the surgeon, is selected.Notably, although described and illustrated for use with an aorticvalve, a heart valve sizer can be used during heart valve replacement ofany of the valves (i.e., mitral valve, tricuspid valve, aortic valve,and pulmonary valve).

In one embodiment, not only is the size and flexibility of the sizerbody 14 analyzed within the aortic root 64 of the patient, but theimplantation technique is also evaluated. In particular, a surgeon usesa selected sizer body 14 and evaluates the sizer body 14 in both asuper-annular and an intra-annular position. This evaluation allows thesurgeon to observe whether a particular size of the sizer body 14 ismore aptly suited for implantation via the super-annular orintra-annular implantation technique. In particular, the surgeonevaluates the size of the outer ring 48 and the annular wall 50 withrespect to the annulus 66 and an annulus opening 68 as well as theflexible conformity of the outer ring 48 to the annulus 66 and theannular wall 50 within the aortic root 64 in both positions. Suchobservation allows the surgeon to determine which implantation techniquewould more beneficially suit the particular patient undergoing the heartvalve replacement surgery.

An alternative embodiment prosthetic heart valve sizer 70 is generallyillustrated in FIG. 5. Heart valve sizer 70 includes the handle 12 and asizer body 72. The handle 12 is similar to the handle 12 described withrespect to the sizer assembly 10 (FIG. 1). The sizer body 72 isrepresentative of a mechanical heart valve 74 illustrated in FIG. 6A. Ina similar manner as described above with respect to the sizer assembly10, the distal end 18 of the handle 12 is permanently or selectivelycoupled to the sizer body 72.

Referring to FIG. 6A, the mechanical heart valve 74 typically includes asewing ring 76, an annular housing 78, and rigid leaflets 80 and 82. Thesewing ring 76 is formed by a flexible and biocompatible cloth 84 whichmay or may not be filled with biocompatible filler and typically definesa circular or parabolic shape. The annular housing 78 is coupled withand extends from the sewing ring 76. In general, the annular housing 78forms an annular extension 85. The rigid leaflets 80 and 82 have pivots(not shown) that rotatably engage an interior surface 86 of the annularhousing 78. Both the housing 78 and the rigid leaflets 80 and 82 aremade of a relatively rigid and biocompatible material. Since the sewingring 76 and the housing 78 each define or possess a different level offlexibility, the overall mechanical heart valve 74 accordingly defines avariable flexibility.

During use, the mechanical heart valve 74 is attached to a valve annulus(not shown) via the sewing ring 76. With this in mind, the mechanicalheart valve 74 is available in a plurality of sizes corresponding to theplurality of sizes of heart valve annuli and valve openings of heartvalve replacement patients. As such, each size of the mechanical heartvalve 74 has a maximum sewing ring diameter D_(D1) and a housingdiameter D_(D2). In addition, the mechanical heart valve 74 has anoverall height HD as defined by the annular housing 78 and the sewingring 76.

As illustrated in FIG. 6A and 6B, the sizer body 72 is representative ofthe mechanical heart valve 74. As such, the sizer body 72 includes anouter ring 88 and an annular wall 90. The outer ring 88 is sized andshaped in a manner similar as described with respect to the sewing ring76. Therefore, the outer ring 88 is circular or parabolic depending uponthe shape of the sewing ring 76 of the mechanical heart valve 74 beingrepresented. As such, the sizer body 72 defines an outer ring maximumdiameter D_(E1) that is substantially equal to, i.e. within 1 mm of, themaximum sewing ring diameter D_(D1) of the mechanical heart valve 74. Inaddition, the outer ring 88 has a flexibility representative of theflexibility of the sewing ring 76. Preferably, the outer ring 88 has aflexibility within 5% to 10% of the flexibility of the sewing ring 76.In one embodiment, the outer ring 88 has a flexibility in the range of90 to 110% of the sewing ring 76. The representative flexibility of theouter ring 88 is achieved in a similar manner as described above withrespect to the outer ring 48 (FIG. 2B).

The annular wall 90 extends from the outer ring 88 in a similar manneras the annular housing 78 extends from the sewing ring 76. As such, theannular wall 90 has a similar size and shape as the annular housing 78.In particular, the annular wall 90 defines a maximum wall diameterD_(E2) that is substantially equal to, i.e. within 1 mm of, the maximumannular housing diameter D_(D2) of the mechanical heart valve 74.Furthermore, the sizer body 72 defines an overall height H_(E)substantially equal to, i.e., within 1 mm of, the overall height H_(D)of the mechanical heart valve 74. In addition, the annular wall 90 has aflexibility representative of the flexibility of annular extension 85.Preferably, the annular wall 90 has a flexibility within 5% to 10% ofthe flexibility of the annular extension 85. In one embodiment, theannular wall 90 each have a flexibility in the range of 90 to 110% ofthe annular extension 85. The representative flexibility of the annularwall 90 is achieved in a similar manner as described above with respectto the annular wall 50 (FIG. 2B).

Notably, since the outer ring 88 and the annular wall 90 each have adifferent flexibility representative of the different flexibilities ofthe sewing ring 76 and the annular extension 85, respectively, theoverall sizer body 72 defines a variable flexibility representative ofthe variable flexibility of the mechanical heart valve 74. Furthermore,the size and the shape of the overall sizer body 72 are representativeof the overall size and shape of the mechanical heart valve 74. In oneembodiment, the sizer body 72 is formed of at least one elastomericmaterial including, but not limited to, santoprene, silicon, andpolyurethane. The sizer body 72 is preferably sterilizable for reuse. Inparticular, the sizer body 72 is preferably formed such that the outersurfaces of the sizer body 72 are substantially continuous to promoteproper sterilization of the sizer body 72 between uses.

The sizer body 72 further includes the handle reception area 60, whichis similar to the handle reception area 60 described with respect to thesizer assembly 10. The handle reception area 60 is preferably centeredwith respect to the annular wall 90. In one embodiment, the handlereception area 60 is connected to the annular wall 90 via a plurality ofspokes 92 circumferentially spaced around the annular wall 90. Each ofthe plurality of spokes 92 extends between and couples the annular wall90 to the handle reception area 60. As such, the sizer body 72 isattached to handle 12 (FIG. 5) via the handle reception area 60 in anyof the manners described above with respect to the sizer body 14 (FIG.1).

Notably, although the sizer body 72 is representative of the mechanicalheart valve 74, it is not necessary for the sizer body 72 to includerepresentations of the rigid leaflets 80 and 82 as illustrated in FIG.6B. However, in embodiments not illustrated, the sizer body 72 includesvalve representations of the rigid valves 80 and 82. The heart valvesizer 70, and more particularly the sizer body 72, is used during heartvalve replacement surgery in a similar manner as described above withrespect to the sizer assembly 10, and more particularly the sizer body14.

FIG. 7 illustrates yet another embodiment of a prosthetic heart valvesizer assembly generally illustrated at 100. The sizer assembly 100includes the handle 12 and a body 102. The handle 12 is similar to thehandle 12 described with respect to the sizer assembly 10. The distalend 18 of the handle 12 is connected to the sizer body 102. The sizerbody 102 includes the sizer body 14 described above. In addition, atraditional cylinder sizer 104 extends form the sizer body 14.

The cylinder sizer 104 extends distally from the outer ring 48 in adirection opposite that of the annular wall 50. The cylinder sizer 104is typically used to determine the diameter of the valve opening withina patient undergoing heart valve replacement surgery. As such, theparticular cylinder sizer 104 placement with respect to the outer ring48 is dependent upon the surgical technique being utilized. Inparticular, for an intra-annular implant technique, the cylinder has adiameter D_(F) substantially equal to, i.e., within 1 mm of, the outerring diameter of D_(B1). Conversely, for a supra-annular implanttechnique, the cylinder sizer 104 has a diameter D_(F) more nearlyrepresentative of the annular wall diameter D_(B2) (FIG. 2B). Thecombination of the cylinder sizer 104 with the outer ring 48 and theannular wall 50 allows a surgeon to utilize prior art sizing techniquesalong with the sizing techniques of the present invention. Notably,although the sizer assembly 100 is illustrated with the sizer body 14representative of a bioprosthetic heart valve 30 (FIG. 2A), the sizerassembly 100 incorporating a cylinder sizer 104 can also be incorporatedin a sizer representative of the mechanical heart valve 74 (FIG. 6A).

Another alternative embodiment of a prosthetic heart valve sizerassembly 110 is generally illustrated in FIG. 8. The sizer assembly 110includes a handle 112, the sizer body 14, similar to the sizer body 14described above with respect to the sizer assembly 10 (FIG. 1), and atraditional cylinder sizer 114. The handle 112 is similar to the handle12 (FIG. 1) described above with respect to the sizer assembly 10 exceptfor those features specifically described herein. The handle 112 definesa first end 116 and a second end 118. The first end 116 is coupled withthe sizer body 14 in a similar manner as described with respect to thehandle 12. The traditional cylinder sizer 114 is coupled with andsubstantially centered on the second end 118 of the handle 112. Thecylinder sizer 114 is coupled with the handle 112 via a snap connection,a threaded connection, or any other spatially feasible and biocompatiblemethod of attachment. Similar to prior art sizers, the cylinder sizer114 defines a diameter D_(G) used to size the valve opening 68(illustrated in FIG. 4) in the patient undergoing prosthetic heart valvereplacement. As such, for an intra-annular implant technique, thediameter D_(G) of the cylinder 114 is substantially equal to the outerring diameter D_(B1) of the sizer body 14. Similarly, a sizer assembly110 used for a supra-annular implant technique includes the cylindersizer 114 in which the diameter D_(G) is substantially equal to, i.e.,within 1 mm of, the wall diameter D_(B2) of the sizer body 14.

During use of the sizer assembly 110, the sizer assembly 110 is placedwithin the aortic root 64 (FIG. 4) of a patient with the cylinder sizer114 as the leading (or distal) end. The cylinder sizer 114 is used bythe surgeon to measure the diameter of the heart valve annulus opening68. During surgery, the surgeon typically has a number of sizes of thesizer assembly 110 available. The surgeon systemically inserts thedifferently sized sizer assembly 110 until the cylinder sizer 114 of thecurrently inserted or selected sizer assembly 110 corresponds with thesize of the particular patient's heart valve opening 68.

Upon determining the proper size of the heart valve opening 68, thesurgeon removes the sizer assembly 110 from the aortic root 64 andsubsequently replaces the sizer assembly 110 into the aortic root 64with the sizer body 14 as the leading (or distal) end. Upon insertion ofthe sizer assembly 110, in particular the sizer body 14, the surgeonfurther evaluates the fit of the sizer body 14 including the size andflexibility of the outer ring 48 and the annular wall 50. Once again itis noted that since the sizer body 14 has a size, shape, and variableflexibility representative of the corresponding bioprosthetic heartvalve 30, the sizer body 14 fits within and conforms to the structureswithin the aortic root 64 in a manner substantially similar to orsubstantially predictive of how the corresponding bioprosthetic heartvalve 30 would fit within and conform to the structures within theaortic root 64. Therefore, upon determination that the sizer body 14 isan appropriate fit to the patient's annulus opening 68, the surgeonselects a bioprosthetic heart valve 30 corresponding to the sizerassembly 110 for implantation.

If the surgeon determines that the body 114 inserted into the patient isinadequate for size or flexibility reasons, he or she removes the sizerassembly 110 and replaces it with a second sizer assembly 110 having aslightly different sized sizer body 14 and repeats the process until asizer assembly 110 is found with a sizer body 14 that most nearlycorresponds to the patients heart valve annulus 66. Upon selection of asizer body 14 that most nearly corresponds to the patient's heart valveannulus 66, the sizer assembly 110 is removed and a bioprosthetic heartvalve 30 is selected that corresponds to the selected sizer assembly110. Notably, although the sizer assembly 110 is illustrated with asizer body 14, which is representative of the bioprosthetic heart valve30, in one alternative embodiment the sizer assembly 110 insteadincorporates a sizer body 72 representative of the mechanical heartvalve 74.

In general, the heart valve sizer in accordance with the presentinvention includes a body with a shape, a size, and a variableflexibility representative of or substantially similar to an availableheart valve prosthesis, such as a bioprosthetic heart valve ormechanical heart valve. These characteristics of the sizer allows asurgeon to not only evaluate the size of an annulus opening but also toevaluate the overall fit and conformity of a particular prosthesis to anannulus and/or within a patient's annulus opening. The evaluation of therepresentative body within the aortic root provides the surgeon withadditional knowledge, thereby, allowing he or she to select a heartvalve prosthesis and/or method of implantation that is more likely tofit and more suitable to the heart annulus of the particular patient.The added certainty concerning the size of the prosthesis and method ofimplantation not only prevents waste of discarded prostheses but alsosaves time during the heart valve replacement surgery, therebybenefiting the overall prognosis of the patient.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges can be made in form and detail without departing from the spiritand scope of the present invention.

1. A flexible sizer body for evaluating a valve annulus to determine asize of a prosthetic heart valve to be sewn to the valve annulus duringheart valve replacement surgery, the prosthetic heart valve including anannular extension having a first flexibility and a sewing ring having asecond flexibility, the flexible sizer body comprising: an outer ringcharacterized by the absence of a cloth cover; and an annular wallcoupled to and extending from the outer ring, the annular wall having aflexibility substantially similar to the first flexibility of theannular extension of the prosthetic heart valve.
 2. The flexible sizerbody of claim 1, wherein the annular wall defines a size and a shapesubstantially similar to a size and a shape of the annular extension ofthe prosthetic heart valve.
 3. The flexible sizer body of claim 1,wherein the annular extension includes an annular housing.
 4. Theflexible sizer body of claim 1, wherein the annular extension includes astent.
 5. The flexible sizer body of claim 4, wherein the annular wallforms a plurality of extremities adapted to selectively deflect inwardlyupon the application of an external force.
 6. The flexible sizer body ofclaim 5, wherein the selective inward deflection characteristic of theplurality of extremities is substantially similar to a selective inwarddeflection of a plurality of stent posts of the annular extension uponapplication of the external force.
 7. The flexible sizer body of claim4, wherein the annular wall forms a plurality of extremities permanentlydeflected inwardly.
 8. The flexible sizer body of claim 1, wherein theouter ring has a flexibility substantially similar to the secondflexibility of the sewing ring of the prosthetic heart valve.
 9. Theflexible sizer body of claim 1, wherein the maximum diameter of theouter ring is substantially similar to a maximum diameter of the sewingring.
 10. The flexible sizer body of claim 1, wherein the outer ring andthe annular wall are each at least partially formed of an elastomericmaterial.
 11. The flexible sizer body of claim 10, wherein the outerring and the annular wall are each formed of at least one of the groupconsisting of santoprene, silicon, and polyurethane.
 12. The flexiblesizer body of claim 1, further comprising: a handle reception area toselectively receive a handle.
 13. The flexible sizer body of claim 1,further comprising: a handle reception area adapted to permanentlyreceive a handle.
 14. The flexible sizer body of claim 1, furthercomprising: a cylinder sizer extending from the outer ring opposite theannular wall.
 15. The flexible sizer body of claim 1, wherein the sizerbody has a variable flexibility substantially similar to a variableflexibility of the prosthetic heart valve.
 16. The flexible sizer bodyof claim 15, the flexible sizer body having an overall size and anoverall shape substantially similar to an overall size and an overallshape of a corresponding prosthetic heart valve.
 17. The flexible sizerbody of claim 1, wherein the flexible sizer body is adapted to interactwith the valve annulus in a manner substantially similar to how thecorresponding prosthetic heart valve would interact with the valveannulus.
 18. The flexible sizer body of claim 1, wherein the outer ringand the annular wall are both parabolic.
 19. The flexible sizer body ofclaim 1, wherein the flexible sizer body is sterilizable for reuse. 20.A sizer assembly for evaluating a valve annulus to determine a size of aprosthetic heart valve to be sewn to the valve annulus during heartvalve replacement surgery, the prosthetic heart valve including anannular extension having a first flexibility and a sewing ring having asecond flexibility, the sizer assembly comprising: a handle defining afirst end and a second end; and a flexible sizer body coupled with thefirst end of the handle, the flexible sizer body including: an outerring characterized by the absence of a cloth cover; an annular wallcoupled to and extending from the outer ring, the annular wall having aflexibility substantially similar to the flexibility of the annularextension of the prosthetic heart valve.
 21. The sizer assembly of claim20, wherein the flexible sizer body further includes: a handle receptionarea adapted to selectively receive the first end of the handle.
 22. Thesizer assembly of claim 20, further comprising: a cylinder sizer adaptedto measure a size of an opening defined by the valve annulus.
 23. Thesizer assembly of claim 22, wherein the cylinder sizer is coupled to andextends from the flexible sizer body opposite the handle.
 24. The sizerassembly of claim 22, wherein the cylinder sizer is selectively coupledto the second end of the handle, the cylinder sizer extending from thehandle opposite an extension of the flexible sizer body.
 25. The sizerassembly of claim 20, wherein the outer ring has a flexibilitysubstantially similar to the flexibility of the sewing ring of theprosthetic heart valve.
 26. The sizer assembly of claim 25, wherein theflexible sizer body has a variable flexibility substantially similar tothe variable flexibility of the prosthetic heart valve.
 27. The sizerassembly of claim 25, wherein the annular wall forms a plurality ofextremities adapted to selectively deflect inwardly upon the applicationof an external force.
 28. The sizer assembly of claim 27, wherein theplurality of extremities are adapted to be deflected inwardly duringinsertion of the flexible sizer body into an opening of the valveannulus.
 29. The sizer assembly of claim 25, wherein the annular wallforms a plurality of extremities permanently deflected inwardly anamount substantially similar to the amount of inward deflection of aplurality of stent posts of the annular extension upon application of anexternal force.
 30. The sizer assembly of claim 20, wherein the flexiblesizer body is sterilizable for reuse.
 31. The sizer assembly of claim20, further comprising: at least one representation of a leaflet of theprosthetic heart valve coupled to the flexible sizer body.
 32. A methodfor evaluating a valve annulus to determine a proper size of aprosthetic heart valve to be sewn to the valve annulus during heartvalve replacement surgery, the prosthetic heart valve including anannular extension having a first flexibility and a sewing ring having asecond flexibility, the method comprising: providing a flexible sizerbody including: an outer ring, and an annular wall coupled to andextending from the outer ring, the annular wall having a flexibilitysubstantially similar to the flexibility of the annular extension of theprosthetic heart valve; inserting the flexible sizer body into anopening of the heart valve annulus to determine whether the flexiblesizer body properly fits and conforms with the heart valve annulus; andselecting the prosthetic heart valve to be sewn in the heart valveannulus based upon the determination of whether the flexible sizer bodyproperty fit and conformed to the heart valve annulus.
 33. The method ofclaim 32, further comprising: repeating the steps of inserting aflexible sizer body into an opening of the heart valve annulus for aplurality of differently configured flexible sizer bodies until one ofthe flexible sizer bodies is determined to fit and conform to the heartvalve annulus.
 34. The method of claim 33, wherein each of thedifferently configured flexible sizer bodies corresponds to adifferently sized prosthetic heart valve.
 35. The method of claim 33,wherein each of the differently configured flexible sizer bodiescorresponds to a different implantation technique.
 36. The method ofclaim 32, further comprising: determining whether the flexible sizerbody is more suitable to interact with the heart valve annulus in anintra-annular or a supra-annular position.
 37. The method of claim 36,further comprising: performing the heart valve replacement surgeryutilizing an implantation technique selected from the group of anintra-annular technique and a supra-annular technique, wherein theimplantation technique is selected based upon the determination of whichposition of the flexible sizer body with respect to the heart valveannulus is more suitable for a particular patient.